In general, an electronic device includes a plurality of substrates. Each of the substrates is connected to a respective one of the other substrates via a connection component such as a connector. In this case, for example, conductive contacts are arranged on the surface of an end portion of each of the substrates. In the connector, there is provided a groove portion for receiving the substrate end portion, and on the inner wall of the groove portion, there are provided contacts on the connector side to make contact with the contacts of the substrate. By inserting the substrate end portion into the groove portion of the connector, the contacts on the substrate make contact with the contacts in the connector groove portion, thereby establishing the electrical connection therebetween. In this case, as falling-off prevention provided between the substrate and the connector (hereinafter, referred to as a “falling-off prevention structure”), the following arrangements have hitherto been provided.
FIG. 1 depicts an example of first falling-off prevention structure. The first falling-off prevention structure is a type without any coming-off prevention mechanism between a substrate 301 and a connector 401. Hereinafter, the substrate is also referred to as a “module”, and the connector is also referred to as a “socket”.
In the example depicted in FIG. 1, an end portion of a substrate 301 is arranged in a groove portion (not depicted) of a connector 401. In FIG. 1, the falling-off prevention is achieved by a pressing force by elasticity of each of the material of the substrate 301 and the connector 401, by a fitting force between the end portion of the substrate 301 and the groove portion of the connector 401, or by a frictional force between the end portion of the substrate 301 and the groove portion of the connector 401 at the time when the end portion of the substrate 301 is inserted into the groove portion of the connector 401. However, in the first falling-off prevention structure, when an external force, oscillation, shock or the like exceeding the pressing force, the fitting force, or the frictional force acts on the first falling-off prevention structure, the connector 401 would fall off from the substrate 301 due to disturbance such as the external force, oscillation, shock, or the like.
FIG. 2 depicts a second falling-off preventing structure. In the second falling-off preventing structure, coming-off prevention mechanism 413 is provided to a connector 411. The coming-off prevention mechanism 413 has a locked state wherein the connection portion between a substrate 311 and the connector 411 is locked, and a released state wherein the connection portion is unlocked. In FIG. 2, the position of each of the coming-off prevention mechanisms 413 in the locked state is indicated by solid lines while the position of the coming-off prevention mechanism 413 in the released state is indicated by a dotted line. As depicted in FIG. 2, in order to ensure an operation space D410, no other members can be disposed within the movable range of the coming-off prevention mechanism 413. Therefore, the construction depicted in FIG. 2 requires operation spaces D410 for releasing the coming-off prevention mechanism 413, and so this operation space D410 becomes an obstacle to high-density mounting.
FIG. 3 depicts a third falling-off preventing structure. The third falling-off preventing structure is a structure for fixing a connector 421 and a substrate 321 to be connected to the connector 421 by a coming-off prevention mechanism 423 (the third falling-off preventing structure is also referred to as a “module holding member”). The coming-off prevention mechanism 423 is fixed to a mating substrate 490 (mother board or the like), which is a connection destination to which the substrate 321 is connected via the connector 421. In FIG. 3, the mating substrate 490 is only partly illustrated, a boundary line between the illustrated part and an omitted part is represented by a dotted line. As in the case of FIG. 3, also in drawings hereinafter, omitted parts are each represented by a curved dotted line. Meanwhile, in order to add a coming-off prevention mechanism to such a structure of which the connector or substrate has no coming-off prevention mechanism in itself, it is necessary to provide a large-scale coming-off prevention mechanism on the substrate. Also in this structure, therefore, there occurs a problem of an occupied space. This is because the coming-off prevention mechanism 423 is fixed to the substrate 490 that mounts the connector 421 thereto. Furthermore, in the structure depicted in FIG. 3, if wind of a cooling mechanism for example a fan, or the like flows thereinto from a direction indicated by an arrow A320, effects of the coming-off prevention mechanism 423 upon the cooling operation presents a problem. Another problem in the structure depicted in FIG. 3 is that, in order to apply this structure to modules mutually different in height or the like, special designs for each module are needed.
[Patent Document 1] Japanese Laid-open Patent Publication No. 08-148223
[Patent Document 2] Published Japanese translation of a PCT application No. 2002-522874
[Patent Document 3] Japanese Registered Utility Model Publication No. 7-35325
[Patent Document 4] Japanese Laid-open Patent Publication No. 2002-75540